Drive mechanisms suitable for use in drug delivery devices

Abstract

The present disclosure is directed to a dose setting mechanism that may be used with a drug delivery device. The dose setting mechanism may include an inner body having a helical thread along an outer cylindrical surface of the inner body, and a drive sleeve for driving a piston rod in an axial direction, the drive sleeve positioned within at least a portion of the inner body. The dose setting mechanism may further include a dose dial sleeve rotatably engaged with the helical thread of the inner body and a dial grip connected to the dose dial sleeve and releasably connected to the drive sleeve. Further when a dose is set, the dial grip is rotated so that both the dose dial sleeve and the drive sleeve rotate with respect to the inner body.

The invention claimed is: 
     
       1. A drug delivery device comprising:
 a housing defining a window; 
 an insert attached to the housing, the insert comprising a maximum dose radial stop, a helical rib extending radially from a surface of the insert; 
 a dose dial sleeve rotatable with respect to the insert, a portion of the dose dial sleeve being visible through the window of the housing, the dose dial sleeve defining a helical groove in which the helical rib of the insert is disposed, the helical rib and the helical groove being configured such that rotation of the dose dial sleeve with respect to the insert causes an axial movement of the dose dial sleeve relative to the insert, a projection extending from the dose dial sleeve, the projection having a stop surface, the stop surface extending parallel to a longitudinal axis of the dose dial sleeve and being configured to contact the maximum dose radial stop of the insert when the dose dial is rotated an amount corresponding to a maximum dose; 
 a driver comprising a first section of a first diameter and a second section of a second diameter; 
 a clutch comprising a plurality of teeth, the clutch being configured to releasably, rotationally couple the dose dial sleeve to the driver; and 
 a threaded piston rod extending through the housing, the threaded piston rod being configured to advance axially as the driver is rotated. 
 
     
     
       2. The drug delivery device of  claim 1 , wherein the projection of the dose dial sleeve and a member forming the maximum dose radial stop of the insert are configured such that relative movement occurs between the projection and the member in a first direction to allow the projection to slide past the member when the dose dial sleeve and the insert are being assembled. 
     
     
       3. The drug delivery device of  claim 2 , wherein the first direction is a first radial direction. 
     
     
       4. The drug delivery device of  claim 3 , wherein the projection of the dose dial sleeve and the member of the insert are configured such that relative radial movement in a second radial direction occurs between the projection and the member after the projection moves past the member when the dose dial sleeve and the insert are being assembled, the second radial direction being opposite the first radial direction. 
     
     
       5. The drug delivery device of  claim 3 , wherein the dose dial sleeve and the insert are configured to be rotated relative to one another in a first rotational direction to assemble the dose dial sleeve and the insert. 
     
     
       6. The drug delivery device of  claim 5 , wherein the dose dial sleeve and the insert are configured such that, after assembly, the stop surface of the projection of the dose dial sleeve contacts the maximum dose radial stop of the insert when the dose dial sleeve is rotated in a second rotational direction the amount corresponding to the maximum dose, the second rotational direction being opposite the first rotational direction. 
     
     
       7. The drug delivery device of  claim 6 , wherein the dose dial sleeve and the insert are configured such that, after assembly, the dose dial sleeve and the insert are prevented from being disassembled from one another when being rotated in the second rotational direction relative to one another due to contact between the stop surface of the projection of the dose dial sleeve and the maximum dose radial stop of the insert. 
     
     
       8. The drug delivery device of  claim 1 , wherein the drug delivery device is configured such that the dose dial sleeve can be rotated in a first rotational direction relative to the insert to increase a set dose. 
     
     
       9. The drug delivery device of  claim 8 , wherein the dose dial sleeve is configured such that the dose dial sleeve can be rotated in a second rotational direction relative to the insert to decrease the set dose without dispensing drug. 
     
     
       10. The drug delivery device of  claim 1 , wherein the dose dial sleeve comprises a dose dial grip. 
     
     
       11. The drug delivery device of  claim 10 , wherein the dose dial grip comprises a plurality of teeth extending proximally from a proximal surface of the dose dial grip. 
     
     
       12. The drug delivery device of  claim 10 , wherein the dose dial grip is rotationally fixed to a distal end of the dose dial sleeve. 
     
     
       13. The drug delivery device of  claim 1 , wherein the dose dial sleeve comprises markings for indicating a selected dose. 
     
     
       14. The drug delivery device of  claim 13 , wherein the window of the housing is configured to make visible to a user the marking corresponding to the selected dose. 
     
     
       15. The drug delivery device of  claim 13 , wherein the markings are reference numerals. 
     
     
       16. The drug delivery device of  claim 15 , wherein the window of the housing is configured to make visible to a user the reference numeral corresponding to the selected dose. 
     
     
       17. The drug delivery device of  claim 1 , wherein the driver is rotationally coupled to the dose dial sleeve. 
     
     
       18. The drug delivery device of  claim 1 , further comprising a button configured to dispense a dose when the button is pressed by a user. 
     
     
       19. The drug delivery device of  claim 18 , wherein the button is configured to, when pressed by the user, apply an axial force to the driver to rotationally couple the dose dial sleeve and the driver via the clutch. 
     
     
       20. The drug delivery device of  claim 1 , further comprising a drug cartridge connected to the housing, the drug cartridge containing a drug. 
     
     
       21. The drug delivery device of  claim 20 , wherein the drug comprises insulin.